Method of manufacturing a light conductive perforated plate

ABSTRACT

A method of manufacturing a perforated plate comprising placing a plurality of tubes in the holes of at least one perforated base plate, and filling the space between the tubes with a material having a lower softening temperature than that of the tubes. This formed block is then cut in a direction transverse to the tubes to form thinner perforated plates.

United Sta Van Esdonk et a1.

1111 3,754,882 [451 Aug. 28, 1973 METHOD OF MANUFACTURING A LIGHT'CONDUCTIVE PERFORATED PLATE Inventors: Johannes Van Esdonk; JacobusHubertus Jacobs, both of Emmasingel, Eindhoven, Netherlands Assignee:U.S. Philips Corporation, New York,

Filed: Dec. 1, 1972 Appl. No.: 311,417

Related U.S. Application Data Continuation-impart of Ser. No. 78,076,Get 5, i970, abandoned.

U.S. C1. 65/42, 65/4, 65/50, 65/56, 65/106, 65/DIG. 7, 350/96 WG Int.Cl. C03b 23/02, C03b 23/20 Field of Search 65/42, 50, 47-49, 65/D1G. 7,4, 106, 36; 350/96 R, 96 W0 References Cited UNITED STATES PATENTS3,237,039 2/1966 Fyler 65/016. 7 3,241,934 3/1966 Granitsas et a1.3,271,036 9/1966 Kuzmickum 3,332,757 7/1967 Hawkins 3,379,217 4/1968Leonard... 3,582,304 6/1971 Bognar....;.. 54/106 X PrimaryExaminer-Robert L. Lindsay, Jr. Attorney-Frank R. Trifari 57 ABSTRACT Amethod of manufacturing a perforated plate comprising placing aplurality of tubes in the holes of at least one perforated base plate,and filling the space he tween the tubes with a material having a lowersoftening temperature than that of the tubes. This formed block is thencut in a direction transverse to the tubes ,to form thinner perforatedplates.

- 7 Claims, 5 Drawing Figures ar ssa: 0a n 55/42.

PATENIEDwcea 1915 3.754382 sum 1 us 2 INVENTORS JOHANNES VAN ESDONKJACOBUS H. JACOBS AGENT PAIfNIfflmczsms 3.754382 swam-2 INVENTORSJOHANNES VAN ESDONK JACOBUS H.JACOBS Y AGENT METHOD OF MANUFACTURING ALIGHT CONDUCTIVE PERFORATEI) PLATE The present application is acontinuation-in-part of U. S. application Ser. No. 78,076, filed Oct. 5,1970 now abandoned.

The invention relates to a method of manufacturing a perforated platecontaining holes which are present at reproducible, accuratelydetermined places, the plate consisting of an insulating material.

For certain cases, for example, picture display panels for television,it is necessary to have the disposal of perforated plates having a largenumber of holes provided at accurately determined places. The drillingof such holes is very time-consuming and difficult to reproduce,particularly if the material of the plate is glass or ceramic material.

In the method according to the invention the manufacture of entirelysimilar plates having a large number of holes and a large area becomespossible in a simple manner if a number of tubes which correspond to thenumber of holes and which consist of a material having a highersoftening temperature than the melting temperature of the material ofthe plate, are placed in holes of at least one perforated base plate,the space between and around the tubes being then filled with thematerial of the plate. In general, when comparatively long tubes areused, said tubes will be placed between two base plates so that they aresupported at either end in the holes of the base plates and can hence bebetter held in parallel. The base plates with the tubes will generallybe placed in an enveloping mould. I

Since the softening temperature of the material of the tubes is higherthan the melting temperature of the material of the plate, the shape ofthe tubes will be maintained so that the holes of said tubes will alsomaintain their transverse dimensions. Thin plates can then be sawn fromthe formed block in a direction at right angles to the longitudinal axisof the tubes. The advantage is that only one or two base plates must beprovided with accurately arranged holes, which base plates can be usedmany times. Tube material can be manufactured accurately in acomparatively simple manner with exactly equal inside and outsidedimensions.

It has provedto be possible that the thin plates sawn from the block canbe bent over a mandrel and, if desirable, can be shaped to form acylinder having truly radially directed holes, after heating thematerial of the plate to the softening temperature. Tubes of ceramicmaterial or a hard type of glass, such as Pyrex or Vycor, areadvantageously used while the material of the plates may consist ofreadily melting glass or meltable ceramic material with acorrespondingly low expansion coefficient. The difference in meltingtemperatures between the tube material and the surrounding glasspreferably is at least 300C. It is also possible to use tubes of a metalthe coefficient of thermal expansion -of which is adapted to correspondto that of the plate material. The tubes are generally made of A1 0,,fired and sintered at l800C. The filling material can be a low meltingceramic material having a composition of MnO -37% by weight, SiO -50% byweight, and Al,0 'l3% by weight with a melting temperature of about1275C. In addition, the plate material may be provided between the tubesin the form of a powder or a paste.

In order that the invention may be readily carried into effect, it willnow be described in greater detail, by

way of example with reference to the accompanying drawings, in whichFIG. 1 is a mould with a moulded block and FIG. 2 is an enlargement of apart shown in FIG. 1.

FIG. 3 is a plan view of a moulded block after removal from the mouldshown in FIG. 1, while FIG. 4 is a perspective elevation and FIG. 5 is across-sectional view of perforated plates obtained by means of themethod according to the invention.

In the method according to the invention, ceramic tubes 2 having holes 3are placed in the holes of two base plates 4 provided accurately at thecorrect places and the assembly is then transferred to a mould 5. A mass1, for example, glass or a ceramic material, is then moulded in theremaining space of the mould 5, the mass 1 filling the space between thetubes 1 entirely (FIGS. 1 and 2). After cooling and hardening of themass 2, the block consisting of the mass 1 with the tubes 2, may beremoved from the mould 5 (FIG. 3). The base plates 4 may then beremoved. By sawing plates from the block in a direction transverse tothe longitudinal direction of the tubes 2, thin perforated flat plateshaving a large number of holes'are obtained, which plates can beentirely equal to one another. Such a plate is shown in FIG. 4. The baseplate 4 can be used many times. In order to avoid the base plate fromadhering to the material of the plate 1, a layer of a suitable material,for example A1 0 may be provided on the base plates.

If desired, a plate as shown in FIG. 4 may be heated until the material1 becomes deformable again and the plate may be bent over a mandrel(FIG. 5), if desirable even to form a cylinder. It is found that theholes remain directed truly radially. Such a bent or cylindrical platemay serve as a grid to form a large number of electron rays. In the axisof the cylinder a cathode is arranged while the tubes 2 may consist ofmetal and may be provided with current supply conductors. A bent plateshape is also of advantage in picture display panels having largedimensions so that it can better withstand external forces.

According to a particular example, there were employed tubes that were30 mm long with a 1.5 mm outside diameter and a 1 mm hole diameter.Plates that were 0.7 to 8 mm thick, each plate having 400 holes, weresawn from a block that was 30 mm thick, 40 mm long, and 30 mm wide.

What is claimed is:

l. A method of manufacturing a perforated plate comprising placing aplurality of tubes in the holes of at least one perforated base plate,the number of tubes corresponding to the number of holes to be providedin said perforated plate, filling the space between said tubes with asolid material having a lower softening temperature than the meltingtemperature of the tubes, heating said material to a softeningtemperature thereof below the melting temperature of said tubes to forma block, and cutting said block transverse to the length of said tubesat a plurality of points thereby to form a thin plate comprising aplurality of apertures.

2. A method of manufacturing perforated plates as claimed in claim 1,wherein placing a plurality of tubes in the holes of at least oneperforated base plate comprises positioning said plurality of tubes sothat their longitudinal axes are parallel to each other.

3. A method of manufacturing perforated plates as claimed in claim 1,wherein the step of filling the space between said tubes comprises,heating said material and tubes to temperatures below the meltingtemperature of the tubes, and cooling said material and tubes to form ablock having said tubes embedded therein.

4. A method of manufacturing perforated plates as claimed in claim 1,further comprising heating the plate to the softening temperature of itsmaterial, and bending said plate over a mandrel to form a cylindricalplate.

5. A method of manufacturing perforated plates as claimed in claim 1,wherein the material of said block and tubes comprises glass and ceramicmaterial, respectively.

6. A method of manufacturing perforated plates as claimed in claim 1,wherein the material of said tubes comprises a harder material than thematerial of said block.

7. A method of manufacturing perforated plates as claimed in claim 1,wherein the material of said tubes comprises a metallic material havinga coefficient of thermal expansion compatible to that of the material ofthe block.

2. A method of manufacturing perforated plates as claimed in claim 1,wherein placing a plurality of tubes in the holes of at least oneperforated base plate comprises positioning said plurality of tubes sothat their longitudinal axes are parallel to each other.
 3. A method ofmanufacturing perforated plates as claimed in claim 1, wherein the stepof filling the space between said tubes comprises, heating said materialand tubes to temperatures below the melting temperature of the tubes,and cooling said material and tubes to form a block having said tubesembedded therein.
 4. A method of manufacturing perforated plates asclaimed in claim 1, further comprising heating the plate to thesoftening temperature of its material, and bending said plate over amandrel to form a cylindrical plate.
 5. A method of manufacturingperforated plates as claimed in claim 1, wherein the material of saidblock and tubes comprises glass and ceramic material, respectively.
 6. Amethod of manufacturing perforated plates as claimed in claim 1, whereinthe material of said tubes comprises a harder material than the materialof said block.
 7. A method of manufacturing perforated plates as claimedin claim 1, wherein the material of said tubes comprises a metallicmaterial having a coefficient of thermal expansion compatible to that ofthe material of the block.